Embodiments of the invention relate to an image sensor and methods of making and using the same.
In general, an image sensor is a semiconductor device for converting optical images into electric signals, and may be classified into a charge coupled device (CCD) and a CMOS (Complementary Metal Oxide Silicon) image sensor. The CMOS image sensor includes a photodiode and at least one MOS transistor in each unit pixel, and sequentially detects the electric signals of each unit pixel through the MOS transistor in a switching mode.
In an image sensor manufacturing process according to a related art, a passivation layer is formed, and then a color filter layer is formed. However, there is a disadvantage in that a relatively large amount of light may be lost in the passivation layer due to the light transmittance characteristics of the passivation layer.
In a pinned photodiode according to the related art, p-type impurity ion implantation is performed in order to reduce or prevent dark current from being generated on a surface of the photodiode. Therefore, there is a problem in that the color reproducibility of blue (B) light having a short wavelength is reduced in a reaction with a surface of a substrate (Si) as compared with green (G) or red (R) colors under the same condition. Further, p-type impurity ions are generally implanted into a surface of Si to prevent dark current on the surface of the Si in a pinned photodiode manufacturing process according to the related art.
However, since blue light has a short wavelength and thus has a photodiode reception range shorter than other colors, a reaction is induced near the surface of the Si. Electrons produced due to the reception of blue light are captured in the aforementioned p-type region. As a result, an output for blue light may deteriorate. That is, according to the related art, since the reaction (or reception) region of blue light is induced near the surface of the Si, there is a problem in that electron generation may be influenced by the implanted p-type region.